How much material??

Hi all, I posted some time ago about being a complete newbie at quilt and want to say thank you for your support in starting a project.
Now, I have been sewing for almost 50 yrs and yes, i do have material I just can't throw away. I have a lot of scraps but how do you know how much is enough to work with?
How do you figure out how much of 1 type of a color or pattern you need?

Sorry for all the questions but this is really confusing. Thanks, Marz

If you are using scraps it is hard to know if you will have enough of one pattern...so I save my scraps for a very scrappy quilt.

If I have some amount of fabric I estimate how many time I want to use it in a block...Say I am doing a 9 patch and I want all the centers to be the same...and I am doing 4" squares...and I will need 16 blocks. I measure my fabric to see if I can get 16 4" squares out of it. Hope that helps

choose a project- start it- if you run out of fabric for it you need to get more if you can get it all done then you had enough
a persons stash is kind of (relative) many of us have extensive stashes- and can create/make quilts for years with it- others need to (suppliment) you only know when you are working on projects- if you choose a pattern and start pulling fabrics out of your stash for the pattern and do not have what you need---you need to do some shopping- or improvise- but there is no way to really know for sure until you start pulling fab's out for the project you are going to work on. my french braid quilt was made completely from stash fabrics- in fact i've been working on stash quilts for a about 4 years now- i do on occassion have to shop- for a coordinate-or blender- or a backing- but 95% of my quilts are created from fabrics i have on hand.